Analytical-Experimental Study on Using Different Control Surfaces to Alleviate Dynamic Loads

Kuzmina, Svetlana I.; Ishmuratov, Fanil; Chedrik, Vasily

doi:10.2514/6.2006-2164

Cited by 6 publications

(3 citation statements)

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“…Here, the maximum amplitude φ achieved in each study is plotted against the wind velocity u ∞ . Larger amplitudes could only be achieved by using an open jet wind tunnel (Ricci and Scotti 2008;Lancelot et al 2017;Kuzmina et al 2006;Saddington et al 2015). Since the fluid dynamic fundamentals are different in open jet wind tunnel, these studies are not included in Fig.…”

Section: Introductionmentioning

confidence: 99%

How to Design a 2D Active Grid for Dynamic Inflow Modulation

Wester

Krauss

Neuhaus

et al. 2022

Flow Turbulence Combust

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In free-field operation, many aerodynamic systems are confronted with changing turbulent inflow conditions. Wind turbines are a prominent example. Here, the rotation of the rotor blades causes incoming wind gusts to result in a local change in the angle of incidence for the blade segments, which changes the effective angle of attack and can lead to dynamic non-linear effects like dynamic stall. Dynamic stall is known to produce a significant overshoot in the acting forces and thus an increase in loads acting on the wind turbine, leading to long-term fatigue. To gain a better understanding, it is necessary to perform wind tunnel experiments under realistic and reproducible inflow with defined conditions. In this study, a so-called 2D active grid is presented, which allows the generation of defined two-dimensional inflow conditions for wind tunnel experiments. The focus is on generating sinusoidal transversal and longitudinal gusts with high amplitudes and frequencies. Different grid configurations and sizes are tested to investigate differences in the generated flow fields. Transversal gusts imposed in this way can be used to study dynamic phenomena without having to move the object under investigation itself. Inertial effects during force measurements and a changing shadow casting due to moving airfoils in particle image velocimetry measurements are thus avoided. The additional possibility to generate defined longitudinal gusts allows to generate a broad range of reproducible inflow situations like yaw or tower shadow effects during experimental investigations.

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Section: Introductionmentioning

confidence: 99%

How to Design a 2D Active Grid for Dynamic Inflow Modulation

Wester

Krauss

Neuhaus

et al. 2022

Flow Turbulence Combust

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show abstract

“…A review of existing gust generators installed around the world is given in [18]. Most gust generators are based on one or multiple pitching airfoils [17][18][19][20][21][22][23][24][25][26][27][28][29]; however, alternative solutions exist. In 1981 Reed [30] built a gust generator for the Transonic Dynamic Tunnel using small pitching surfaces mounted on the sidewall of the tunnel.…”

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confidence: 99%

Improving Wind Tunnel “1-cos” Gust Profiles

Balatti

Khodaparast

Friswell

et al. 2022

Journal of Aircraft

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“…Research Institute/University Year Top speed Wind tunnel cross section NASA (USA) [12] 1966 30.5 m/s Rectangular 0.6 m × 0.9 m NASA (USA) [13] 1969 76.2 m/s Rectangular 2.13 m × 3.05 m MIT (USA) [86] 1974 37 m/s Elliptical 2.13 m × 3.32 m Duke University (USA) [18] 1996 25m/s Rectangular 0.7 m × 0.53 m Virginia Tech (USA) [77] 2004 15 m/s Square 2.15 m × 2.15 m TSAGI (Russia) [78] 2005 30 m/s Elliptical 4.0 m × 2.33 m TSAGI (Russia) [78] 2005 120 m/s Circular 7 m diameter University of Maryland (USA) [87] 2008 N/A N/A Politecnico di Milano (Italy) [79] 2008 30 m/s Rectangular 1.0 m × 1.5 m University of Colorado (USA) [88] 2009 20 m/s Square 0.34 m × 0.34 m DLR (Germany) [16] 2010 Mach 0.75 Square 1.0 m × 1.0 m ONERA (France) [80] 2011 Mach 0.73 Rectangular 0.76 m × 0.8 m Cranfield University (England) [81] 2015 14.5 m/s Elliptical 1.52 m ×1.14 m ARA (England) [19] 2015 Mach 0. [83] 2019 25 m/s Square 0.9 m × 0.9 m Michigan State University (USA) [84] 2021 10 m/s Square 0.61 m × 0.61 m Mitsui engineering (Japan) [85] N/A 20 m/s N/A Example of conventional gust generators (a, directly adapted from [14]; b, directly adapted from [15]; c, directly adapted from [16])…”

Section: Generation Of Gusts In the Wind Tunnelmentioning

confidence: 99%

Numerical and experimental studies of aeroelastic hinged wingtips

Balatti¹

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Aeroelasticity is the science that investigates the mutual interaction between aerody-namic, elastic, and inertia forces and how this affects the static and dynamic structural response. Aeroelastic models can be defined considering different levels of fidelity de-pending on the models’ aim. Gust loads are among the most critical cases an aircraft can encounter, and so mitigating the loads enables the design of a lighter structure, consequently reducing production and fuel consumption costs. Hinged wingtips have shown potential to improve the wing aerodynamic performance while alleviating struc-tural loads. The aim of this work is the numerical and experimental study of aeroelastic wings with hinged wingtips subjected to gusts. Measurements from wind tunnel tests are used to validate the numerical model. Two numerical models, representative of the same aircraft with hinged wingtips subjected to gusts, were considered, a detailed and a simplified one. The latter model, due to its low number of degrees of freedom, was used for wingtip design optimisation. Gust and turbulence events cannot be measured di-rectly, but they can be identified from in-flight measurements. Cubic B-spline functions were used for gust identification considering simulated flight data from the simplified and detailed models. Results have shown the ability of the simplified model to identify the gust and turbulence considering simulated data from the detailed model. To validate the numerical models, a gust generator was designed, installed and commissioned for the Swansea University wind tunnel. Experimental results have shown the difficulty of creating a perfect ‘1-cos’ gust at the desired location. Two techniques to improve the ‘1-cos’ gust were considered. In the first case, the transfer function between the vane rotation and the gust produced at the aircraft model location was identified, and its in-verse was used to calculate the vane rotation. The improvements using this approach are limited by the strong nonlinearity of the aerodynamics. A parametric study of the vane rotation has shown that a more complicated vane rotation function allows ‘1-cos’ gusts at the aircraft model location to be obtained with a mean square error two orders of magnitude smaller than the initial case. An elastic wing able to accommodate different wingtips was manufactured. Three wingtips, namely a fixed wingtip, a hinged wingtip, and a hinged wingtip with a torsional spring at the hinge were considered. Static and dynamic wind tunnel tests have shown the potential of hinged wingtips in reducing wing gust loads. Measured gust loads were used to validate the aeroelastic models.

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Analytical-Experimental Study on Using Different Control Surfaces to Alleviate Dynamic Loads

Cited by 6 publications

References 1 publication

How to Design a 2D Active Grid for Dynamic Inflow Modulation

How to Design a 2D Active Grid for Dynamic Inflow Modulation

Improving Wind Tunnel “1-cos” Gust Profiles

Numerical and experimental studies of aeroelastic hinged wingtips

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